Mycotoxin Contamination Of Foods Research Articles

Effect of application method and formulation on prothioconazole residue behavior and mycotoxin contamination in wheat

In this study, efficient and sensitive analytical methods based on liquid chromatography-tandem mass spectrometry were established to evaluate the degradation behavior of prothioconazole and prothioconazole-desthio along with mycotoxin contamination in wheat samples. The mean recoveries of prothioconazole and prothioconazole-desthio ranged from 76.05% to 96.17% with intraday relative standard deviations (RSDs) of 0.84%–14.38%. Mean recoveries of the five mycotoxins were 85.82%–103.24% with RSDs of 1.82%–7.03%. The residue and degradation behavior of prothioconazole was studied in wheat plant and grain under field conditions with different spraying equipment and prothioconazole formulations. Both application method and formulation affected prothioconazole degradation, and the content of all mycotoxin was lower than the national standards. The proposed analytic methods can be used to systematically evaluate prothioconazole and prothioconazole-desthio along with mycotoxin contamination in food. These results suggest that prothioconazole is safe for the control Fusarium head blight in wheat.

Aflatoxin-degrading Bacillus sp. strains degrade zearalenone and produce proteases, amylases and cellulases of agro-industrial interest

Zearalenone, an oestogenic mycotoxin produced by Fusarium sp., occurs naturally in agricultural commodities. Economic losses and health concerns associated to mycotoxins has attracted research interest towards exploring novel approaches to detoxify mycotoxin-contaminated food and feed. The aim of the present work was to study the ability of 11 aflatoxin-degrading Bacillus strains to degrade ZEA. In addition, a qualitative assessment of protease, amylase and cellulase activity of the studied Bacillus strains was made. All strains were able to degrade 58–96.9% ZEA after 72 h. Toxicity towards Artemia salina was significantly reduced (P < 0.0001). Degradation extracts fluorescence decreased 50% indicating a probable cleavage of the lactone ring. Strains RC1A, RC3A and RC6A showed a remarkable enzymatic activity, showing potential to be used as feed additives.

Current PCR-based methods for the detection of mycotoxigenic fungi in complex food and feed matrices

Mycotoxins are toxic secondary fungal metabolites produced by certain types of filamentous fungi, such asAspergillus, Fusarium, andPenicillium spp. Mycotoxigenic fungi and their produced mycotoxins are considered to be an important issue in food and feed safety due to their toxic effects like carcinogenicity, immunosuppression, neurotoxicity, nephrotoxicity, and hepatotoxicity on humans and animals. To boost the safety level of food and feedstuff, detection and identification of toxins are essential at critical control points across food and feed chains. Zero-tolerance policies by the European Union and other organizations about the extreme low level of tolerance of mycotoxins contamination in food and feed matrices have led to an increasing interest to design more sensitive, specific, rapid, cost-effective, and safer to use mycotoxigenic fungi detection technologies. Hence, many mycotoxigenic fungi detection technologies have been applied to measure and control toxins contamination in food and feed substrates. PCR-based mycotoxigenic fungi detection technologies, such as conventional PCR, real-time PCR, nested PCR, reverse transcriptase (RT)-PCR, loop-mediated isothermal amplification (LAMP),in situ PCR, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR DGGE), co-operational PCR, multiplex PCR, DNA arrays, magnetic capture-hybridization (MCH)-PCR and restriction fragment length polymorphism (RFLP), would contribute to our understanding about different mycotoxigenic fungi detection approaches and will enhance our capability about mycotoxigenic fungi identification, isolation and characterization at critical control points across food and feed chains. We have assessed the principles, results, the limit of detection, and application of these PCR-based detection technologies to alleviate mycotoxins contamination problem in complex food and feed substrates. The potential application of these detection technologies can reduce mycotoxins in complex food and feed matrices.

Occurrence and preventive strategies to control mycotoxins in cereal-based food.

Mycotoxins contamination in cereal-based food is ubiquitous according to systematic review of the scientific documentation of worldwide mycotoxin contamination in cereal and their products between 2008 and 2018, thus representing food safety issue especially in developing tropical countries. Food processing plays a vital role to prevent mycotoxin contamination in food. Therefore, it is with great urgency to develop strategies to inhibit fungi growth and mycotoxin production during food processing. This review begins by discussing physicochemical properties of five most common mycotoxins (aflatoxins, fumonisins, ochratoxins, deoxynivalenol, and zearalenone) found in cereal grains, regulation for mycotoxins in food, and their potential negative impact on human health. The fate of mycotoxins during major cereal-based food processing including milling, breadmaking, extrusion, malting, and brewing was then summarized. In the end, traditional mitigation strategies including physical and chemical and potential application of biocontrol agent and essential oil nanoemulsions that can be applied during food processing were discussed. It indicated that no single method is currently available to completely prevent mycotoxin contamination in cereal foods.

Development of an Escherichia coli-based electrochemical biosensor for mycotoxin toxicity detection

Mycotoxin contamination in food and feed is a global concern because mycotoxin contamination can cause both acute and chronic health effects in humans and animals. In the present work, an Escherichia coli-based biosensor is described for the toxicity assessment of aflatoxin B1 (AFB1) and zearalenone (ZEN). In this electrochemical biosensor, E. coli is used as the signal recognition element, p-benzoquinone is used as the mediator, and a two-step reaction procedure has been developed to separate the mediator from the mycotoxins. The current value of the as-prepared microbial biosensor exhibits a linear decrease with concentrations of AFB1 and ZEN in the range of 0.01–0.3 and 0.05–0.5 μg/mL, with detection limits reaching 1 and 6 ng/mL, respectively. The IC25 values obtained by the present method are 0.25 and 0.40 μg/mL for AFB1 and ZEN, which shows that the cytotoxicity of AFB1 to E. coli is more severe than the cytotoxicity of ZEN to E. coli. The combined toxic effect of these two mycotoxins has also been explored, and synergistic biotoxicity has been observed. Moreover, the biosensor is successfully applied to the toxicity evaluation of mycotoxins in real samples, including peanut and corn oils. This work could provide new insight into mycotoxin and microorganism interactions and could establish a new approach for future mycotoxin detection.

Mycotoxins in Children’s Food: Problem and Halal Management

&#x0D; &#x0D; &#x0D; &#x0D; Mycotoxins are ubiquitous compounds found in the natural life cycle of food- producing plants. They have a range of diverse chemical and physical properties and toxicological effects on man and animal. Mycotoxins are considered the most important contaminants of the food chain due to their chronic adverse effects on health and the economy. Mycotoxins are known as the 21th century “Great Masquerader” due to its complex natural history involving different tissues and resembling different diseases at each stage in its evolution. Mycotoxins can induce a variety of clinical symptoms including epistaxis, conjunctivitis, coughing, apnea, wheezing, vomiting and nausea. Some mycotoxins induce acute pulmonary hemorrhage, bone marrow failure and pneumonia. Knowledge about these symptoms enables the clinician to ask questions for possible exposure to the main classes of mycotoxins to protect children from sources of such exposure. These sources may include food, clothes, furniture and indoor air at home. Early childhood exposure to mycotoxins may be critical determinants of later health effects. Exposure in utero and through early infancy may additionally be important. Several well-known diseases such as neural tube defects, liver and esophageal cancers are associated with the consumption of mycotoxin-contaminated food. Knowledge of previous short or long term exposure to mycotoxins may help paediatricians to more accurately diagnose and provide treatment options to children and their families. The current review discusses the problems associated with the occurrence of different common mycotoxins in children’s food and the possible halal strategies to counteract these problems. &#x0D; &#x0D; &#x0D; &#x0D;

Biocontrol of toxigenic Aspergillus strains isolated from baby foods by essential oils

AbstractEssential oils are natural antimicrobial agents that can be used to control fungal and mycotoxin contamination. Although there are numerous reports discussing the fungal and mycotoxin contamination of foods, there are few researches on baby food contamination so this work aimed to determine the fungal and mycotoxin contamination in cerelac, cornflakes and milk powder and tried to control the mycotoxigenic strain growth and their production of mycotoxins by using essential oils. Cornflakes were heavily contaminated (24 species including 9 genera), while cerelac and milk powder were less contaminated. Aspergillus and Penicillium were the prevalent genera. The produced aflatoxins and ochratoxins from the tested strains of Aspergillus flavus and A. niger were extracted and estimated by fluorometric method. We used the 18S rRNA sequence technique to identify the genotypes of the three isolates. Two isolates were identified as Aspergillus niger and the third isolate as A. flavus. Omt‐A gene was detected in the A. flavus, while Aopks gene was detected in A. niger isolates. Amongst the five used essential oils, only cumin and peppermint oil depressed the mycotoxigenic strain growth and peppermint oil had the highest result. Its inhibitory effect on aflatoxin and ochratoxin production was evaluated. Aflatoxin production was highly reduced by 52.1%, but ochratoxin inhibition was very low, 4.88% and 3.17% by A. niger obtained from cornflakes and milk powder, respectively. The three tested samples were contaminated by ochratoxins, but cerelac and milk powder samples were free of aflatoxins. Cornflakes sample recorded the highest reading for both toxins.

Protective Effects of Bacillus subtilis ANSB060, Bacillus subtilis ANSB01G, and Devosia sp. ANSB714-Based Mycotoxin Biodegradation Agent on Mice Fed with Naturally moldy Diets.

Mycotoxins are toxic secondary metabolites produced by toxigenic fungi that commonly contaminate agricultural crops. The purpose of the current study was to evaluate whether Bacillus subtilis ANSB060, Bacillus subtilis ANSB01G, and Devosia sp. ANSB714-based mycotoxin biodegradation agent (MBA) could alleviate the negative effects of naturally moldy diet containing aflatoxin (AF), zearalenone (ZEN), and deoxynivalenol (DON) on growth performance, serum immune function, and antioxidant capacity as well as tissue residues in mice. A total of 54 mice were randomly divided into three dietary treatments: basal diet (CON), multi-mycotoxins contaminated diet (MCD) containing AF, ZEN and DON and multi-mycotoxins contaminated diet plus MBA at a dose of 1.0 g kg-1 feed (MCD + MBA). Mice fed with moldy diet showed a significant decrease in body weight gain (p < 0.05), whereas the relative weight of the liver, spleen and uterus were remarkably increased (p < 0.05). Serum IgA and IgM contents were significantly decreased in MCD treatment compared with that in CON treatment (p < 0.05). In contrast, serum interleukin-1β (IL-1β), interleukin-2 (IL-2), and interleukin-6 (IL-6) concentrations were significantly promoted in mice fed with moldy diet (p < 0.05). Besides, the exposure to mycotoxins caused marked down-regulation of serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in mice (p < 0.05). The addition of MBA effectively counteracted these toxic effects of moldy diet on mice. And DON residues in kidneys of mice consuming moldy diet were eliminated by the supplementation with MBA. Taken together, Bacillus subtilis ANSB060, Bacillus subtilis ANSB01G, and Devosia sp. ANSB714-based mycotoxin biodegradation agent has great potential use as a microbial additive to counteract mycotoxins contamination in food and feed.

Understanding Mycotoxin Contamination Across the Food Chain in Brazil: Challenges and Opportunities.

Brazil is one of the largest food producers and exporters in the world. In the late 20th century, the European Union program for the harmonization of regulations for contaminants in food, including mycotoxins, led to the examination of mycotoxin contamination in foods at a global level. The problem of the rejection of food by the European Union and other countries became a Brazilian national priority because of economic and food safety aspects. Ochratoxin A in coffee and cocoa and aflatoxins in Brazil nuts are examples of the impact of technical trade barriers on Brazilian foods. To overcome these threats, several strategies were undertaken by Brazilian and international organizations. In this context, the Codex Commission on Food Contaminants (CCCF) has emerged as a forum to discuss with more transparency issues related to mycotoxins, focusing on establishing maximum levels and codes of practices for some commodities and mycotoxins to ensure fair trade and food safety. Our experience in investigating and understanding mycotoxin contamination across the food chains in Brazil has contributed nationally and internationally to providing some answers to these issues.

Annexin A3 may play an important role in ochratoxin-induced malignant transformation of human gastric epithelium cells

Ochratoxin A (OTA), one of the most abundant food-contaminating mycotoxins, is a possible carcinogen to humans. We previously demonstrated that long-term (40 weeks) OTA exposure induces the malignant transformation of human gastric epithelium cells (GES-1) in vitro. However, the specific mechanism underlying OTA-induced gastric carcinogenesis is complex. In the present study, we used 2-DE and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI/TOF MS) combined with bioinformatics and immunoblotting to investigate the differentially expressed proteins between GES-1 and OTA-malignant transformed GES-1 cells (OTA-GES-1T cells) in vitro. We found that four differentially expressed proteins were identified after malignant transformation, including actin, cytoplasmic 1 (ACTB), F-actin-capping protein subunit alpha-1 (CAPZA1), Annexin A3 (ANXA3), thioredoxin peroxidase B from red blood cells (TPx-B) and Fibrinogen beta B (Fibrinogen β). Among the differentially expressed proteins, the effect of Annexin A3 was analyzed by MTT assay, western blot, cell cycle analysis, wound healing assay, Transwell assay, and colony formation assay in OTA-GES-1T cells. The results showed that inhibition of Annexin A3 by siRNA effectively prevented the proliferation, migration, and invasion abilities of OTA-GES-1T cells. Collectively, the results of this study will guide future research on OTA carcinogenicity.

Specific antigen-based and emerging detection technologies of mycotoxins.

Mycotoxins are secondary fungal metabolites produced by certain types of filamentous fungi or molds, such as Aspergillus, Fusarium, Penicillium, and Alternaria spp. Mycotoxins are natural contaminants of agricultural commodities, and their prevalence may increase due to global warming. According to the Food and Agriculture Organization of the United Nations, approximately 25% of the world's food crops are annually contaminated with mycotoxins. Mycotoxin-contaminated food and feed pose a high risk to both human and animal health. For instance, they possess carcinogenic, immunosuppressive, hepatotoxic, nephrotoxic, and neurotoxic effects. Hence, various approaches have been used to assess and control mycotoxin contamination. Significant challenges still exist because of the complex heterogeneous nature of food and feed composition. The potential of antigen-based approaches, such as enzyme-linked immunosorbent assay, flow injection immunoassay, chemiluminescence immunoassay, lateral flow immunoassay, and flow-through immunoassay, would contribute to our understanding about mycotoxins' rapid identification, their isolation, and the basic principles of the detection technologies. Additionally, we address other emerging technologies of potential application in the detection of mycotoxins. The data included in this review focus on basic principles and results of the detection technologies and would be useful as benchmark information for future research. © 2019 Society of Chemical Industry.

The influence of milling and sifting processes on deoxynivalenol distribution in whole-wheat flour and its products

Milling and sifting of grain are important processes that affect mycotoxin distribution in the chain of grain products. The level of deoxynivalenol (DON) in white flour cannot be reduced by sifting because it is concentrated within a specific white flour fraction. The objective of this study was to investigate the influence of milling and sifting processes on the reduction of DON contamination in whole-wheat flour and in the chain of spring wheat products (grain – bran – white flour – white flour fractions) from artificially and naturally (2016) and naturally (2017) infected grain samples. The current study showed that the distribution of DON in the grain products (whole-wheat flour – bran – white flour) depends on the weather conditions of the season and grain contamination level. This was particularly evident in the naturally contaminated grain in 2017. The highest DON concentrations were determined in bran. Higher DON concentrations in the bran from the naturally infected grain indicate the protective function of the grain hull, which provides partial protection for grain embryo against higher contamination. With a delay in harvesting, which resulted in increased DON concentrations, bran remained the most contaminated product; however, this was not true for the products from artificially infected grain. The DON level in bran was not significantly different atP&lt;0.05 from that in whole-wheat flour from artificially infected grain, it indicates that after inoculation, bran had biochemical compounds capable of significantly diminishing trichothecene production. It was investigated that DON levels were concentrated in white flour fractions 160 and 112 μm from naturally infected grains and in white flour fraction (residues) from artificially and naturally infected grains harvested later. The results obtained in this study could be further used for developing novel strategies aimed at limiting mycotoxin contamination in food and feed.

Mycotoxins contamination in foods consumed in Uganda: A 12-year review (2006–18)

Abstract Mycotoxins are secondary fungal metabolites with a potential to have adverse effects on humans and animals. The rationale of this review was to examine the current status of mycotoxins in Uganda and the problems associated with these toxins. The commonly studied mycotoxins in Uganda are aflatoxins and fumonisins with aflatoxin B1 being the most prevalent. The review has shown that aflatoxin contamination reduces economic growth by 0.26% in Uganda owing to decline in productivity. Uganda loses 577 US million dollars annually as a result of 3700 aflatoxin-induced liver cancer cases. Aflatoxins contamination of sorghum, maize and peanuts causes a decline in exports valued at 7.48 US million dollars which accounts for 45% reduction in total agricultural exports. There are no fully developed strategies for the control of mycotoxins contamination in food and food products in Uganda. Regulations for monitoring foods susceptible to aflatoxins contamination should be put in place and strict measures on the quality of food at both household and market levels be enforced by all policy makers.

Mycotoxin Contamination of Food and Associated Health Risk in Cameroon: A 25-years Review (1993-2018)

Mycotoxin Contamination of Food and Associated Health Risk in Cameroon: A 25-years Review (1993-2018)

Aflatoxin B1 Degradation and Detoxification by Escherichia coli CG1061 Isolated From Chicken Cecum.

Aflatoxin B1 (AFB1) is one of the most hazardous mycotoxins contamination in food and feed products, which leads to hepatocellular carcinoma in humans and animals. In the present study, we isolated and characterized an AFB1 degrading bacteria CG1061 from chicken cecum, exhibited an 93.7% AFB1 degradation rate by HPLC. 16S rRNA gene sequence analysis and a multiplex PCR experiment demonstrated that CG1061 was a non-pathogenic Escherichia coli. The culture supernatant of E. coli CG1061 showed an 61.8% degradation rate, whereas the degradation rates produced by the intracellular extracts was only 17.6%, indicating that the active component was constitutively secreted into the extracellular space. The degradation rate decreased from 61.8 to 37.5% when the culture supernatant was treated with 1 mg/mL proteinase K, and remained 51.3% when that treated with 100°C for 20 min. We postulated that AFB1 degradation was mediated by heat-resistant proteins. The content of AFB1 decreased rapidly when it was incubated with the culture supernatant during the first 24 h. The optimal incubation pH and temperature were pH 8.5 and 55°C respectively. According to the UPLC Q-TOF MS analysis, AFB1 was bio-transformed to the product C16H14O5 and other metabolites. Based on the results of in vitro experiments on chicken hepatocellular carcinoma (LMH) cells and in vivo experiments on mice, we confirmed that CG1061-degraded AFB1 are less toxic than the standard AFB1. E. coli CG1061 isolated from healthy chicken cerum is more likely to colonize the animal gut, which might be an excellent candidate for the detoxification of AFB1 in food and feed industry.

Advances in the development of detection techniques for mycotoxins in vegetable oil

Mycotoxins are low-molecular-weight secondary metabolites produced by different fungal species, which can cause teratogenic, hepatotoxic, nephrotoxic, carcinogenic, hemorrhagic, and immunosuppressive effects, and damage the reproductive system in humans and other mammals. Mycotoxins are often present at low concentrations in the matrices and present a branch of compounds, homologs, and isomers. Vegetable oil is one of the top mycotoxin-contaminated foods. Vegetable oil contains lipids, fatty acids, and pigments, which have the potential to increase matrix effects and damage instruments. Therefore, the establishment of high-efficient sample pretreatment methods, and highly sensitive and high-throughput detection techniques are big challenges for the accurate determination of various mycotoxins in vegetable oil. In the present study, the current status and development trends of mycotoxin detection methods in different vegetable oils have been reviewed. Different pretreatment methods such as liquid-liquid extraction, solid phase extraction, gel permeation chromatography, dynamic covalent hydrazine chemistry, and QuEChERS are also summarized. Additionally, characteristics of detection techniques such as gas chromatography, liquid chromatography, tandem mass spectrometry, and immunosensors are discussed.

Label-Free Electrochemical Sensor for Ochratoxin A Using a Microfabricated Electrode with Immobilized Aptamer

Ochratoxin A (OTA) is one of the most abundant food-contaminating mycotoxins that is also a potential carcinogen and responsible for many diseases affecting humans. Consequently, a sensitive, portable device for the detection of OTA is highly desirable. In this study, a miniaturized electrochemical aptamer-based sensor was developed for the label-free, sensitive detection of OTA. For the construction of the sensor, a gold thin-film three-electrode system was fabricated using standard microfabrication techniques on a polystyrene substrate (25 mm × 25 mm). Subsequently, the thiol-modified linker, 6-mercaptohexanol, DNA aptamer, and methylene blue (MB) were sequentially applied to the working electrode to construct a sensing layer. MB served as a redox indicator that interacted with the aptamer via the guanine bases and phosphate backbone to form complexes. The addition of OTA to the sensor induced the folding of the aptamer, which was accompanied by the release of the aptamer–MB–OTA complex from the sensor....

Histology-guided high-resolution AP-SMALDI mass spectrometry imaging of wheat-Fusarium graminearum interaction at the root\u2013shoot junction

BackgroundFungal pathogens like Fusarium graminearum can cause severe yield losses and mycotoxin contamination of food and feed worldwide. We recently showed its ability to systemically colonize wheat via root infection. However, the molecular response of wheat to Fusarium root rot (FRR) infection and systemic spread is still unknown. As a molecular camera, mass spectrometry (MS) imaging combines label-free and multiplex metabolite profiling with histopathology.ResultsAtmospheric-pressure (AP)-SMALDI-MS imaging was combined with optical microscopy to study wheat-F. graminearum interaction at the root–shoot junction, which is a crucial line of defense against a pathogen that can invade all distal plant parts. To scope the functional, temporal and local aspects of FRR disease spread, metabolic changes were simultaneous visualized in diseased and healthy stem bases of the resistant cultivar Florence-Aurore at 10, 14 and 21 days after root inoculation. Histological information was used to identify disease relevant tissues and to assist the interpretation of molecular images. Detected mycotoxin compounds secreted by F. graminearum showed a route of stem infection that was consistent with observations made by microscopy. The outer epidermis and vasculature of leaf sheath were, at different disease stages, identified as prominent sites of pathogen migration and wheat protection. Wheat metabolites mapped to these relatively small tissues indicated cell wall strengthening and antifungal activity as direct defenses as well as conservation in the wheat reactions to F. graminearum diseases that affect different plant organs.ConclusionsAP-SMALDI-MS imaging at high spatial resolution is a versatile technique that can be applied to basic and applied aspects of agricultural research. Combining the technology with optical microscopy was found to be a powerful tool to gain in-depth information on almost unknown crop disease. Moreover, the approach allowed studying metabolism at the host–pathogen interface. The results provide important hints to an understanding of the complex spatio-temporal organization of plant resistance. Defense-on-demand responses to pathogen ingress were found, which provide opportunities for future research towards an improved resistance that does not negatively impact yield development in the field by saving plant resources and, moreover, may control different Fusarium diseases.

Inhibition or Stimulation of Ochratoxin A Synthesis on Inoculated Barley Triggered by Diffuse Coplanar Surface Barrier Discharge Plasma.

Ochratoxin A (OTA) is one of the most abundant food-contaminating mycotoxins. Besides their high toxicity, mycotoxins are highly stable to physical, chemical or biological detoxification. Therefore, the treatment with cold atmospheric plasma could be one approach to reduce the amount of mycotoxins in different products. The aim of this study was to determine the influence of cold atmospheric plasma on the inactivation of Aspergillus niger and Penicillium verrucosum inoculated on barley and their production of OTA. Inoculated barley was treated with plasma generated by dry air, CO2 or CO2 + O2 for 1 or 3 min and stored for up to two weeks at 9, 25, or 37°C. Three minutes of air plasma treatment effectively significantly reduced the total mold count of both microorganisms by 2.5–3 log cycles. The production of OTA from A. niger was only low, therefore the treatment effect was indistinguishable. The treatment of P. verrucosum on barley after an incubation of five days using a CO2 + O2 plasma resulted in a reduction of the OTA content from 49.0 (untreated) to 27.5 (1 min) and 23.8 ng/g (3 min), respectively. In contrast, CO2 plasma caused an increase of the OTA amount from 49.0 (untreated) to 55.8 (1 min) and 72.9 ng/g (3 min). Finally, the use of air plasma resulted likewise in a decrease of the OTA concentration from 56.9 (untreated) to 25.7 (1 min) and 20.2 ng/g (3 min), respectively. Reducing the incubation time before the treatment to 24 h caused in contrast an increase of the OTA content from 3.1 (untreated) to 29.1 (1 min) and 20.7 ng/g (3 min). Due to the high standard deviation, these changes were not significant, but the tendencies were clearly visible, showing the strong impact of the plasma gas on the OTA production. The results show, that even if the total mold count was reduced, under certain conditions the OTA amount was yet enhanced, probably due to a stress reaction of the mold. Concluding, the plasma gas and incubation conditions have to be considered to allow a successful inactivation of molds and in particular their toxic metabolites.

Homogeneous Quenching Immunoassay for Fumonisin B1 Based on Gold Nanoparticles and an Epitope-Mimicking Yellow Fluorescent Protein.

Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity, sensitivity, and speed. On the basis of a previously identified epitope-mimicking peptide, or mimotope, we developed a homogeneous fluorescence quenching immunoassay based on gold nanoparticles (AuNPs) and a recombinant epitope-mimicking fusion protein for the detection of mycotoxin fumonisin B1 (FB1). The fumonisin mimotope was cloned as a fusion protein with a yellow fluorescent protein that could be used directly as the tracer for FB1 detection without the need of labeling or a secondary antibody. Furthermore, owing to the fluorescence quenching ability of AuNPs, a homogeneous immunoassay could be performed in a single step without washing steps to separate the unbound tracer. The homogeneous quenching assay showed negligible matrix effects in 5% wheat extract and high sensitivity for FB1 detection, with a dynamic range from 7.3 to 22.6 ng mL-1, a detection limit of 1.1 ng mL-1, and IC50 value of 12.9 ng mL-1, which was significantly lower than the IC50 value of the previously reported assay using the synthetic counterpart of the same mimotope in a microarray format. The homogeneous assay was demonstrated to be specific for fumonisins B1 and B2, as no significant cross-reactivity with other mycotoxins was observed, and acceptable recoveries (86% for FB1 2000 μg kg-1 and 103% for FB1 4000 μg kg-1), with relative standard deviation less than 6.5%, were reported from spiked wheat samples, proving that the method could provide a valuable tool for simple analysis of mycotoxin-contaminated food samples.